So I just ordered a 302 performance long block with High compression pistons (hyperutectic), hardened connecting rod bolts, balanced, a performance cam and GT40 heads from MABBCO. I went with the straight GT40 heads because they told me the header fitment would be easier. I'm topping it off with a Trick Flow Track Heat intake and 75mm TB. I am replacing the 4.0 in my 2003 Ranger with this beauty along with an Explorer AOD and rear end. I'm using the Advance Adapter to keep my transfer case. I will be using a Dakota Digital interface for the speedometer control.

I believe you have the newest Ranger I have ever seen done, keep us posted and pics would be nice. This site isn't as happening as it once was but there is still some action. If they check in there are some pretty smart hombres here. Good luck with the build and again pics

I will post pics as I can. My bigest obstacles were the speedometer and headers but I have them both solved! For the speedometer I will be using Dakota Digitals SGI-5E Signal Generator. It will take the input signal from the AOD VSS and convert it before sending it to the PCM. I guess this has been a headache for a lot of people doing this swap. As for the headers, Advance Adapter makes a set of headers that will work for my application since I am not using the GT40"P" heads. The combustion chamber is a bit small so you get more compression but it's minimal. However, the exhaust valve on the straight GT40 heads is larger so the flow is better. I consider it an even swap. But, because the spark plugs are not angled as they are on GT40P heads, the options for headers is better.

It's true the GT40 has a larger exhaust valve, but it is incorrect to assume that the GT40 flows better because of this. Flow tests have shown the stock GT40p exhaust port to flow just a tad better than the GT40 exhaust port (both in stock condition). Now once you port either of them, all bets are off. At that point, it becomes a question of how well the porting was done.

But you are right the choices in headers for the GT40 are better and despite flow characteristics make it the "easier" choice for a V8 Ranger conversion.

Have you determined what EEC you'll use to control it all with? Being you are putting this in a 2003, my guess is a 2001 Explorer EEC would have most all of the functionality your 2003 needs...possibly even including the dash controls for the speedo. However being you've already solved that with the Dakota box, I suspect this is going to be a carb-n-dizzy engine.

Your mention of an Explorer AOD is confusing though. All the V8 Explorers came with 4R70w transmissions. Or were you just using AOD generically to refer to a 4 speed automatic).